1. Field of the Invention
This invention is in the field of quick-release bicycle axle fasteners.
2. Description of Prior Art
Cam-operated quick-release axle fasteners for bicycles have been available for years, but the original designs have inherent disadvantages. If the cam is accidentally left open or is knocked open during riding, or if the cam force adjustment is too loose, the wheel can fall off the bicycle during riding. To overcome this, fork makers designed "safety" drop-outs with outer surfaces having depressions, holes, or tabs which engage a complementary portion of the fastener. This retains the axle despite a loose cam. However, these devices reduced the convenience of quick-release fasteners, and introduced another safety problem. With "safety" drop-outs, opening the cam is not enough to release the axle. The user must also loosen an adjustment nut to clear the safety retention surface. To reinstall the axle, the user must re-tighten the adjustment nut to eliminate this clearance. This requires re-adjusting the cam tension on each use. Many users are not competent to perform this adjustment, resulting in a cam that is either dangerously loose or tight in the closed position.
Below are examples of prior efforts to improve the safety of quick-release axle fasteners. None of them provides an adjustment nut with a stopping point adjustment that stops the adjustment nut at the predetermined position to provide correct clamping tension on each use, as with the present invention.
U.S. Pat. No. 4,400,038 (Hosokawa) has a safety mechanism which prevents axle release until the cam lever is fully rotated. U.S. Pat. No. 4, 964,287 (Gaul) uses a cam with a removable lever or key for security. U.S. Pat. No. 4,805,941 (Segawa, FIGS. 4,5) offers a spring loaded safety interlock 5. U.S. Pat. No. 4,805,941 (Downing) has a safety hook for holding the axle in the dropout.